JP2008030350A - Method of manufacturing toothed belt - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of molding and vulcanizing a rubber belt, e.g. a toothed belt or a cogged belt, which allows effective use of the entire surface of a press board and ensures molding of even a belt having a short circumference. <P>SOLUTION: The method of vulcanizing a belt includes a process of holding a part of a cylindrical belt sleeve at least between an upper and a lower press platens 100, molding and vulcanizing by heating and pressurization and shifting the heating and vulcanizing point in order, so as to finally mold and vulcanize all the circumference of the belt sleeve. A toothed belt is molded and vulcanized without cooling of the press mold. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  It relates to a manufacturing method when manufacturing a belt made of rubber such as a toothed belt or a cogged belt. Specifically, the entire area of the press mold can be used effectively, even in the case of a belt with a short circumference. The present invention relates to a method of manufacturing a belt capable of reliably molding a tooth part.

  Conventionally, as a method of manufacturing a double-sided toothed belt, a canvas, a core wire, an unvulcanized rubber sheet, and a canvas are sequentially laminated on an inner mold having a groove forming a tooth portion, and a cylindrical grooved rubber mother is formed on the outer surface thereof. After inserting the mold, heat and pressurize the rubber layer into the groove of the inner mold and the master mold to form the teeth on the upper and lower surfaces of the belt, or the teeth on one side molded and vulcanized with a toothed mold. Then, a toothed belt is formed on the back side of the toothed belt by laminating an unvulcanized rubber sheet and a rubberized canvas in sequence using a grooved press mold to partially form teeth and add There was a method of performing vulcanization, changing the pressing position by progressive feeding, and finally forming a tooth portion on the entire circumference and obtaining a vulcanized double-sided toothed belt.

  However, the method of laminating an unvulcanized rubber sheet on the back of a toothed belt sleeve having teeth on one side and partially vulcanizing the belt sleeve and vulcanizing the entire circumference while repeating this procedure one at a time The tooth part around the belt cannot be molded and vulcanized, and as described above, the pressing position is changed by forward feed, and the method of completing the molding and vulcanization of the entire circumference in a plurality of processes is adopted. However, the heat of the press mold is transmitted not only to the portion sandwiched between the press dies but also to the rubber sheet located in the vicinity thereof. Then, the vulcanization of the rubber progressed by heating, and it was in a somewhat cured state, and there was a problem that the shape of the tooth part did not come out sufficiently even if it was put between press dies and tried to mold .

  Therefore, for example, as shown in Patent Document 1, through holes for passing cooling water are provided at both ends of the press mold to adjust the temperature of the mold to be low, and vulcanization is performed at both ends of the press mold. There is no such thing. By doing so, a relatively clear vulcanization boundary can be created, heat can be prevented from entering near the end of the press mold, and vulcanization can be prevented. The part shape can be obtained.

JP-A-62-135353

  Certainly, by cooling both ends of the press mold, it is possible to clarify the vulcanization boundary and reduce the heat transfer to the unpressed part. Although it can prevent the problem that the tooth shape cannot be improved, the belt cannot be heated in the cooling part of the press mold. It cannot be said that it is in an efficient state where heating is carried out using the.

  In addition, the temperature of the mold inevitably decreases not only in the part where the press mold is cooled, but also in the vicinity of the press mold. This also leads to problems such as variations in physical properties, and the formation of a tooth profile or the like that cannot be sufficiently performed at a low temperature portion, resulting in a belt having a poor shape.

  Therefore, the present invention can efficiently mold the teeth by using the entire surface of the mold, there is little temperature difference between the center and the end of the mold, and there is no variation in vulcanization. An object of the present invention is to provide a method for producing a belt that can be molded well.

  In order to achieve the above object, in claim 1 of the present invention, at least a part of a cylindrical belt sleeve is sandwiched between upper and lower press dies and heated and pressurized to form and vulcanize, and then heated and pressurized. In a manufacturing method of a toothed belt including a step of sequentially moving the position and finally forming and vulcanizing the entire circumference of the belt sleeve, the shape of the tooth portion is formed on the belt sleeve without cooling the end portion of the press die. It has the process.

According to a second aspect of the present invention, the method for manufacturing a toothed belt according to the first aspect is characterized in that the number of times of molding by heating and pressing is two or more per tooth.
According to a third aspect of the present invention, in the method for producing a toothed belt according to the first or second aspect, the molding time by heating and pressing is 0.5 to 3 minutes per tooth.
In Claim 4, it is set as the manufacturing method of the toothed belt of Claims 1-3 whose circumference of the belt sleeve to vulcanize is the range of 400-1000 mm.

  According to the first aspect, since the tooth portion of the belt sleeve is formed without cooling the press die used when vulcanizing the belt sleeve with the press die, the sleeve is efficiently heated on the entire surface of the press die. The molding and vulcanization can be completed in a short time.

  According to the second aspect, the number of times of molding by heating and pressurization is two times or more per tooth, and even if the heating time of one time is shortened, the tooth portion can be molded and sufficient vulcanization can be performed. it can.

  According to the third aspect of the present invention, the time for molding by heating and pressing is set to 0.5 to 3 minutes per tooth, and the heating time is extremely short, so that the periphery of the mold does not have to be cooled at the end of the press mold. Is not heated and vulcanization does not proceed.

  According to the fourth aspect of the present invention, the belt sleeve has a peripheral length in the range of 400 to 5500 mm. With such a short peripheral belt, the size of the mold is small, so that the temperature of the mold can be obtained by cooling the end. However, in the method of the present invention, the heating time is shortened to minimize the heat entering the mold periphery, so there is no need to cool the mold. The temperature can also be made sufficiently high.

  As an example of a belt to which the vulcanizing method of the present invention is applied, for example, a center belt 3 used for a high load transmission belt 1 having a plurality of blocks 2 mounted along the longitudinal direction shown in FIG. .

  FIG. 5 shows a high-load transmission belt 1 using a center belt having teeth on both sides manufactured by the manufacturing method of the present invention, and a rope-shaped core wire 5 is embedded in a spiral in rubber 4. And two blocks of the same width, and a block 2 having grooves 6 and 7 for fitting the center belts 3a and 3b on the side surfaces 2a and 2b.

  The raw rubber used for the center belts 3a and 3b includes hydrogenated nitrile rubber, chloroprene rubber, chlorosulfonated polyethylene, alkylated chlorosulfonated polyethylene and other rubbers having improved heat aging properties, natural rubber, Styrene butadiene rubber and tolyl rubber are used. In the above rubber, carbon black, zinc white, stearic acid, plasticizer, anti-aging agent, etc. are added as compounding agents, and sulfur and organic peroxides are added as vulcanizing agents. The vulcanizing agent is not particularly limited.

  As the core wire 15, a glass rope treated with an RFL solution or rubber paste, or an organic fiber such as an aramid fiber rope treated with an adhesive such as an RFL solution, an epoxy solution, an isocyanate solution and rubber paste, or the like. Used.

  Teeth 10 and 11 are formed on the upper and lower surfaces 8 and 9 of the center belts 3a and 3b at a predetermined pitch, and the recesses 12 and 13 between the teeth 10 and 11 are formed in the grooves 6 and 7 of the block 2. As will be described later in FIG. Both block side surfaces 2a and 2b of the block 2 are inclined surfaces that engage with the V-grooves of the pulleys, and receive the power from the driven pulleys and are locked and fixed to the center belts 3a and 3b. The power of the driving pulley is transmitted to the driven pulley. Cover canvases 12 and 13 are laminated on the upper and lower surfaces of the center belts 3a and 3b.

  As shown in FIG. 4, the block 2 includes an upper beam portion 14 and a lower beam portion 15 and a center pillar 16 that connects the central portions of the upper and lower beam portions 14 and 15. Grooves 6 and 7 into which the center belts 3a and 3b are fitted are formed. Further, as shown in FIG. 3, on the upper and lower surfaces of the groove in the groove 6, a ridge portion 17 that engages with a ridge portion 12 provided on the upper surface 8 of the center belt 3 and a ridge portion 13 provided on the lower surface 9, 18, the block 2 and the center belts 3a and 3b are locked and fixed.

  As the block resin, polyamide resin, polyamideimide (PAI) resin, polyphenylene sulfide (PPS) resin, polybutylene terephthalate (PBT) resin, polyimide (PI) resin, polyethersulfone (PES) resin, Synthetic resins such as polyetheretherketone (PEEK) resin are used, but among them, they have low friction coefficient, excellent wear resistance, rigidity and elasticity against bending, and can be easily damaged. Resin which does not end up is good, and it can be said that polyamide resin, especially 4,6-nylon is preferable.

The belt vulcanizing method according to the present invention will be described below with reference to the accompanying drawings.
As a manufacturing method of such a center belt, a canvas that becomes an inner layer 4a having unevenness including a concave portion 19 on one surface is obtained by placing and pressing a cover canvas 101 and a rubber sheet 102 on a mold 100 having unevenness. The attached composite sheet 103 is produced (FIG. 1). The composite sheet 103 is cut to a predetermined circumference, wound around a cylindrical mold 104, the core wire 105 is spun from above, an adhesive rubber layer (not shown) is wound, and further outward A belt sleeve having teeth on one side is prepared by heating and pressurizing in a vulcanizing can (not shown) with a jacket made of vulcanized rubber.

  The side of the sleeve 106 that has been removed from the mold is polished to a predetermined thickness, and the rubber sheet 107 that forms the outer layer 4b and the cover canvas 108 are laminated (FIG. 2). Pressing between the lower mold 100 having an uneven shape meshing with the unevenness produced above and the upper mold 109 having an uneven shape for providing unevenness on the newly laminated rubber sheet 107, the outer layer side is pressed. Also, irregularities including the concave portion 18 are formed, the tooth portion is molded, and then the rubber is vulcanized (FIG. 3). Tooth can be formed on the entire circumference of the belt sleeve and vulcanized by forming a tooth part in the unvulcanized portion in the forward feed and vulcanizing. Then, the center belt can be manufactured by cutting to a predetermined width.

  The press mold 100 used in the belt vulcanizing method of the present invention does not pass cooling water at both ends, and can heat the unvulcanized rubber sheet 107 over the entire surface. Molding vulcanization by the press mold 100 is performed in the following cycle.

  As shown in FIG. 4, since the entire surface of the belt sleeve cannot be heated at the same time in this press mold 100, the belt sleeve 110 is rotated in the press mold 100 by partially heating and rotating the toothed pulley 110. The part that has not yet been heated is moved and heated and pressed by the press die 100. By repeating this operation, heating is performed in order to form the irregularities that become the tooth portions on the entire circumference of the belt sleeve, and further, the vulcanization of the unvulcanized rubber is completed by heating and pressing. Although the cooling water is not passed through both ends of the press mold 100 used in the present invention, the heating time for one time is set to a range of 1 to 5 minutes and an extremely short time. We will do it at least twice per location. If the clamping by the press mold is performed without overlapping, when the belt sleeve is heated and pressed in order, the belt sleeve rotates at least twice.

  By setting the heating time for one time to a short time, the part that is not in contact with the mold is hardly heated and the vulcanization hardly proceeds, so it is necessary to pass cooling water through the end of the mold. Therefore, the entire mold can be efficiently used for heating.

  The heating temperature is set in the range of 150 to 180 ° C, and if it is less than 150 ° C, heating must be performed many times to obtain a sufficient degree of vulcanization due to insufficient temperature, and the tooth profile is poorly formed. turn into. If the temperature exceeds 180 ° C., the temperature is too high, and even when heated for a short time, the amount of heat applied to the rubber that is not in contact with the mold is increased, leading to variations in vulcanization, which is not preferable.

  The applied pressure is set in the range of 0.5 to 5 MPa (surface pressure). If the surface pressure is less than 0.5 MPa, pressurization is insufficient and the shape of the tooth part cannot be sufficiently obtained. About the upper limit, pressurization of about 5 MPa is sufficient for molding, and pressurization beyond that There is no point in doing it.

  Moreover, it is appropriate to perform one pressurization time in the range of 0.5 to 3 minutes. If it is less than 0.5 minutes, the pressurization is still insufficient, and the shape of the tooth portion cannot be sufficiently obtained. Even if it is heated for more than 3 minutes, a lot of heat is transmitted to the rubber in the adjacent part beyond the range sandwiched by the press mold, and vulcanization proceeds. For example, since the rubber is somewhat cured by being in a semi-vulcanized state, it is not preferable because a clean tooth profile cannot be formed even if the portion is pressed next to mold the tooth portion.

  The number of times of heating and pressing varies depending on the heating temperature, but the number of times varies depending on the heating temperature, but is at least twice per tooth and is usually repeatedly heated and pressurized in the range of 2 to 6 times. If it is less than 2 times, sufficient heating and molding cannot be performed, leading to a problem that predetermined physical properties cannot be obtained due to insufficient vulcanization, and over vulcanization will result in overvulcanization. This is not preferable.

  The belt sleeve to be vulcanized preferably has a circumference of 400 to 1000 mm. With such a short circumference belt, the size of the mold becomes small, so that it is difficult to sufficiently raise the temperature of the mold if the structure is cooled at the end. Since it is shortened to minimize the heat entering the mold periphery, the mold need not be cooled and the mold temperature can be sufficiently increased.

  Examples of the type of belt applied in the belt vulcanization method of the present invention include belts such as double-sided toothed belts and double cog belts that perform partial vulcanization by progressive feeding using a press die. For example, it can be applied as a vulcanization method for a center belt used for a belt that is mounted with a block as shown in FIG. 5 and transmits a high load. Of course, other belts also use a press die. Any material that can be molded and vulcanized can be used.

(Example 1)
A core formed of a rope formed by twisting a canvas and aramid fibers using a cylindrical mold having grooves on the surface at a predetermined interval and a weft thread in the longitudinal direction of the belt and a nylon thread having a stretchability and an aramid thread in the belt width direction. , Wrapped with 0.7mm thick unvulcanized rubber made of hydrogenated nitrile rubber composition, covered with a vulcanized rubber jacket and heated in a vulcanized can at 170 ° C for 20 minutes Vulcanization was carried out, and after cooling, unvulcanized rubber and a canvas comprising a hydrogenated nitrile rubber composition were wound around.

  The obtained cylindrical laminated body was hung between two-shaft toothed pulleys, and a part of the laminated body was sandwiched between press pulleys by a press die and heated and pressurized. No cooling is performed at both ends of the press die, and the pressing conditions are a temperature of 165 ° C. and a surface pressure of 2 MPa × 2 minutes at one time. When one round is made by rotating the half length of the steel plate in order, the press is performed twice per place over the entire circumference. When the unevenness forming the tooth part is completed, the unvulcanized rubber is then completely vulcanized, so that the tooth part is finally formed by pressing at a temperature of 165 ° C. and a surface pressure of 2 MPa × 20 minutes. And reached a predetermined degree of vulcanization.

  The thickness of the bottom of the obtained belt was measured with a micrometer, the tooth tip, the root R and the tooth height were measured with a shape measuring machine, and the working time required for molding vulcanization was measured. The results are shown in Table 1.

(Example 2)
In the same manner as in Example 1, a canvas, a core wire, and an unvulcanized rubber sheet are wound around a mold and molded and vulcanized to form a tooth portion on one side, and a non-vulcanized rubber sheet is wound on the other side Created the body. The obtained cylindrical laminated body was hung between two-shaft toothed pulleys, and a part of the laminated body was sandwiched between press pulleys by a press die and heated and pressurized. The both ends of the press mold are not cooled, and the pressing conditions are a temperature of 165 ° C. and a surface pressure of 2 MPa × 0.5 min. When one round is made by rotating half the length of the mold in order, the press is performed twice per place over the entire circumference. When the unevenness forming the tooth part is completed, the unvulcanized rubber is then completely vulcanized, so that the tooth part is finally formed by pressing at a temperature of 165 ° C. and a surface pressure of 2 MPa × 21 minutes. And reached a predetermined degree of vulcanization.

(Example 3)
In the same manner as in Example 1, a canvas, a core wire, and an unvulcanized rubber sheet are wound around a mold and molded and vulcanized to form a tooth portion on one side, and a non-vulcanized rubber sheet is wound on the other side Created the body. The obtained cylindrical laminated body was hung between two-shaft toothed pulleys, and a part of the laminated body was sandwiched between press pulleys by a press die and heated and pressurized. The both ends of the press mold are not cooled, and the pressing conditions are a temperature of 165 ° C. and a surface pressure of 2 MPa × 0.5 min. If it makes two rounds by rotating half the length of the mold in order, this means that the press was performed four times per place over the entire circumference. When the unevenness forming the tooth part is completed, the unvulcanized rubber is then completely vulcanized, so that the tooth part is finally formed by pressing at a temperature of 165 ° C. and a surface pressure of 2 MPa × 22 minutes. And reached a predetermined degree of vulcanization.

(Comparative Example 1)
A laminate in which a canvas, a core wire, and an unvulcanized rubber sheet are wound around a mold in the same manner as in the examples, molded and vulcanized to form teeth on one side, and an unvulcanized rubber sheet is wound on the other side It was created. The laminate was suspended between biaxial toothed pulleys, and a part of the laminate was sandwiched between press pulleys by a press die and heated and pressurized. Cooling water is passed through both ends of the press mold, and the press conditions are as follows: temperature is 130 ° C., surface pressure is 2 MPa × 15 minutes, one press is performed per location, and the laminate is rotated one turn to make one turn. Zhou was typed. When the unevenness forming the tooth part is completed, the unvulcanized rubber is then completely vulcanized, so that the tooth part is finally formed by pressing at a temperature of 165 ° C. and a surface pressure of 2 MPa × 20 minutes. And reached a predetermined degree of vulcanization.

  The thickness of the bottom of the obtained belt was measured with a micrometer, the tooth tip, the root R and the tooth height were measured with a shape measuring machine, and the working time required for molding vulcanization was measured. The results are shown in Table 1.

(Comparative Example 2)
A laminate in which a canvas, a core wire, and an unvulcanized rubber sheet are wound around a mold in the same manner as in the examples, molded and vulcanized to form teeth on one side, and an unvulcanized rubber sheet is wound on the other side It was created. The laminate was suspended between biaxial toothed pulleys, and a part of the laminate was sandwiched between press pulleys by a press die and heated and pressurized. No cooling is performed at both ends of the press mold, and the press conditions are a temperature of 130 ° C., a surface pressure of 2 MPa × 15 minutes, one press per location, and the laminate is rotated one turn to make one turn. The whole circumference was typed. When the unevenness forming the tooth part is completed, the unvulcanized rubber is then completely vulcanized, so that the tooth part is finally formed by pressing at a temperature of 165 ° C. and a surface pressure of 2 MPa × 20 minutes. And reached a predetermined degree of vulcanization.

  The thickness of the bottom of the obtained belt was measured with a micrometer, the tooth tip, the root R and the tooth height were measured with a shape measuring machine, and the working time required for molding vulcanization was measured. The results are shown in Table 1.

  As can be seen from the results in Table 1, when the belt vulcanized by the vulcanization method of the present invention and Comparative Example 1 are compared, it is understood that almost the same belt thickness and tooth shape are obtained. The working time is shortened by about 60 minutes, which is considered to be due to the fact that the entire surface can be efficiently heated without cooling the end of the mold.

  In Comparative Example 2, a mold that does not pass cooling water is used at the end of the mold, and the time required for the vulcanization operation is not much different from that of the example, but the belt shape is different from the example. Largely, it is thought that the formation of the tooth part by molding is not good because heat is transmitted to the part off the press die and vulcanization proceeds.

  Further, in Comparative Example 2, when pressing only two times with a heating and pressing time of 0.5 minutes, the pressing time is too short and the variation in belt thickness is large, whereas in Comparative Example 3, the same heating force is applied. Even if the pressing time is 0.5 minutes, the belt thickness variation can be suppressed by pressing four times. Therefore, even if the time is short, it can be compensated by increasing the number of presses at the time of molding. However, if the time is further shorter than 0.5 minutes, the press circumference increases and an effect cannot be expected to be shortened.

  It is a vulcanization method that can be used mainly when vulcanizing while shaping teeth and cogs such as a double-sided toothed belt or double cog belt.

It is sectional drawing when the unevenness | corrugation of the inner layer side was shape | molded with the metal mold | die. It is sectional drawing of the place which laminated | stacked the rubber sheet and cover canvas of the outer layer side. It is sectional drawing of the place which shape | molds the unevenness | corrugation by the side of an outer layer with a metal mold | die. It is a schematic diagram of the place where it is heated and pressurized with a press die. It is a perspective schematic diagram showing an example of the high load transmission belt concerning the present invention. It is a sectional side view of a high load power transmission belt.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 High load power transmission belt 2 Block 3a Center belt 3b Center belt 4 Rubber | gum 4a Inner layer 4b Outer layer 5 Core 11 Upper beam part 12 Lower beam part 13 Center pillar 14 Groove 15 Groove 16 Groove upper surface 17 Groove lower surface 18 Groove part 19 Groove Part 20 Projection part 21 Projection part 100 Mold 101 Cover canvas 102 Rubber sheet 103 Composite sheet 104 Mold 105 Core wire 106 Sleeve 107 Rubber sheet 108 Cover canvas 109 Mold 110 Toothed pulley

Claims (4)

  At least a part of the cylindrical belt sleeve is sandwiched between upper and lower press dies and heated and pressurized to form and vulcanize, and the position of heating and pressing is moved sequentially to finally form and vulcanize the entire belt sleeve circumference. A method for manufacturing a toothed belt comprising a step of forming a shape of a tooth portion on a belt sleeve without cooling the end portion of the press die.   The method for manufacturing a toothed belt according to claim 1, wherein the number of times of molding by heating and pressing is two or more per tooth.   The method for producing a toothed belt according to claim 1 or 2, wherein the molding time by heating and pressing is 0.5 to 3 minutes per tooth. The method for manufacturing a toothed belt according to claim 1, wherein the circumference of the belt sleeve to be vulcanized is in the range of 400 to 1000 mm.

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